MUC1 568 A/G genotype-dependent Cancer Antigen 15-3 levels in breast cancer patients

Objectives: CA 15-3 is a widely used tumor marker for breast cancer. We have investigated whether the MUC1 568 A/G polymorphism can influence CA 15-3 levels in healthy women and patients with breast tumors. Design and methods: CA 15-3 was measured in 208 healthy women, in 67 with benign disease, and in 162 women with breast cancer. All subjects were genotyped for the MUC1 568 A/G polymorphism. Results: Significant differences were observed between mean CA 15-3 levels of control subjects grouped according to the MUC1 568 genotype (mean ± SD): AA (10.3 ± 3.8), AG (15.9 ± 5.0) and GG (19.0 ± 5.6) U/mL, p < 0.0001. Similar (median) results were observed in women with benign breast disease: AA (10.2), AG (14.2) and GG (16.6) U/mL, p < 0.0001, and those with breast cancer: AA (10.4), AG (17.1) and GG (23.9) U/mL, p < 0.0001. Conclusions: The MUC1 568 A/G polymorphism strongly influences CA 15-3 levels in healthy women and women with either benign or malignant breast tumors.